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freebsd-skq/lib/libc/net/getaddrinfo.c
Alfred Perlstein 1c71deff79 balance parens. 
Submitted by: mbr
2002-02-05 23:56:29 +00:00

1976 lines
45 KiB
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/* $FreeBSD$ */
/* $KAME: getaddrinfo.c,v 1.15 2000/07/09 04:37:24 itojun Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* "#ifdef FAITH" part is local hack for supporting IPv4-v6 translator.
*
* Issues to be discussed:
* - Thread safe-ness must be checked.
* - Return values. There are nonstandard return values defined and used
* in the source code. This is because RFC2553 is silent about which error
* code must be returned for which situation.
* - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is
* invalid.
* current code - SEGV on freeaddrinfo(NULL)
* Note:
* - We use getipnodebyname() just for thread-safeness. There's no intent
* to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to
* getipnodebyname().
* - The code filters out AFs that are not supported by the kernel,
* when globbing NULL hostname (to loopback, or wildcard). Is it the right
* thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG
* in ai_flags?
* - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.
* (1) what should we do against numeric hostname (2) what should we do
* against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready?
* non-loopback address configured? global address configured?
* - To avoid search order issue, we have a big amount of code duplicate
* from gethnamaddr.c and some other places. The issues that there's no
* lower layer function to lookup "IPv4 or IPv6" record. Calling
* gethostbyname2 from getaddrinfo will end up in wrong search order, as
* follows:
* - The code makes use of following calls when asked to resolver with
* ai_family = PF_UNSPEC:
* getipnodebyname(host, AF_INET6);
* getipnodebyname(host, AF_INET);
* This will result in the following queries if the node is configure to
* prefer /etc/hosts than DNS:
* lookup /etc/hosts for IPv6 address
* lookup DNS for IPv6 address
* lookup /etc/hosts for IPv4 address
* lookup DNS for IPv4 address
* which may not meet people's requirement.
* The right thing to happen is to have underlying layer which does
* PF_UNSPEC lookup (lookup both) and return chain of addrinfos.
* This would result in a bit of code duplicate with _dns_ghbyname() and
* friends.
*/
/*
* diffs with other KAME platforms:
* - other KAME platforms already nuked FAITH ($GAI), but as FreeBSD
* 4.0-RELEASE supplies it, we still have the code here.
* - AI_ADDRCONFIG support is supplied
* - some of FreeBSD style (#define tabify and others)
* - classful IPv4 numeric (127.1) is allowed.
*/
#include "namespace.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <rpc/rpc.h>
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
#include <netdb.h>
#include <resolv.h>
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include <ctype.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#ifdef DEBUG
#include <syslog.h>
#endif
#include <syslog.h>
#include <stdarg.h>
#include <nsswitch.h>
#include "un-namespace.h"
#if defined(__KAME__) && defined(INET6)
# define FAITH
#endif
#define SUCCESS 0
#define ANY 0
#define YES 1
#define NO 0
static const char in_addrany[] = { 0, 0, 0, 0 };
static const char in6_addrany[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static const char in_loopback[] = { 127, 0, 0, 1 };
static const char in6_loopback[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
};
static const struct afd {
int a_af;
int a_addrlen;
int a_socklen;
int a_off;
const char *a_addrany;
const char *a_loopback;
int a_scoped;
} afdl [] = {
#ifdef INET6
#define N_INET6 0
{PF_INET6, sizeof(struct in6_addr),
sizeof(struct sockaddr_in6),
offsetof(struct sockaddr_in6, sin6_addr),
in6_addrany, in6_loopback, 1},
#define N_INET 1
#else
#define N_INET 0
#endif
{PF_INET, sizeof(struct in_addr),
sizeof(struct sockaddr_in),
offsetof(struct sockaddr_in, sin_addr),
in_addrany, in_loopback, 0},
{0, 0, 0, 0, NULL, NULL, 0},
};
struct explore {
int e_af;
int e_socktype;
int e_protocol;
const char *e_protostr;
int e_wild;
#define WILD_AF(ex) ((ex)->e_wild & 0x01)
#define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02)
#define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04)
};
static const struct explore explore[] = {
#if 0
{ PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
#endif
#ifdef INET6
{ PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
{ PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
{ PF_INET6, SOCK_RAW, ANY, NULL, 0x05 },
#endif
{ PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
{ PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
{ PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
{ PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
{ PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
{ PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 },
{ -1, 0, 0, NULL, 0 },
};
#ifdef INET6
#define PTON_MAX 16
#else
#define PTON_MAX 4
#endif
static const ns_src default_dns_files[] = {
{ NSSRC_FILES, NS_SUCCESS },
{ NSSRC_DNS, NS_SUCCESS },
{ 0 }
};
#if PACKETSZ > 1024
#define MAXPACKET PACKETSZ
#else
#define MAXPACKET 1024
#endif
typedef union {
HEADER hdr;
u_char buf[MAXPACKET];
} querybuf;
struct res_target {
struct res_target *next;
const char *name; /* domain name */
int qclass, qtype; /* class and type of query */
u_char *answer; /* buffer to put answer */
int anslen; /* size of answer buffer */
int n; /* result length */
};
static int str_isnumber __P((const char *));
static int explore_fqdn __P((const struct addrinfo *, const char *,
const char *, struct addrinfo **));
static int explore_null __P((const struct addrinfo *,
const char *, struct addrinfo **));
static int explore_numeric __P((const struct addrinfo *, const char *,
const char *, struct addrinfo **));
static int explore_numeric_scope __P((const struct addrinfo *, const char *,
const char *, struct addrinfo **));
static int get_canonname __P((const struct addrinfo *,
struct addrinfo *, const char *));
static struct addrinfo *get_ai __P((const struct addrinfo *,
const struct afd *, const char *));
static int get_portmatch __P((const struct addrinfo *, const char *));
static int get_port __P((struct addrinfo *, const char *, int));
static const struct afd *find_afd __P((int));
static int addrconfig __P((struct addrinfo *));
#ifdef INET6
static int ip6_str2scopeid __P((char *, struct sockaddr_in6 *));
#endif
static struct addrinfo *getanswer __P((const querybuf *, int, const char *, int,
const struct addrinfo *));
static int _dns_getaddrinfo __P((void *, void *, va_list));
static void _sethtent __P((void));
static void _endhtent __P((void));
static struct addrinfo *_gethtent __P((const char *, const struct addrinfo *));
static int _files_getaddrinfo __P((void *, void *, va_list));
#ifdef YP
static struct addrinfo *_yphostent __P((char *, const struct addrinfo *));
static int _yp_getaddrinfo __P((void *, void *, va_list));
extern int _yp_check __P((char **));
#endif
static int res_queryN __P((const char *, struct res_target *));
static int res_searchN __P((const char *, struct res_target *));
static int res_querydomainN __P((const char *, const char *,
struct res_target *));
static char *ai_errlist[] = {
"Success",
"Address family for hostname not supported", /* EAI_ADDRFAMILY */
"Temporary failure in name resolution", /* EAI_AGAIN */
"Invalid value for ai_flags", /* EAI_BADFLAGS */
"Non-recoverable failure in name resolution", /* EAI_FAIL */
"ai_family not supported", /* EAI_FAMILY */
"Memory allocation failure", /* EAI_MEMORY */
"No address associated with hostname", /* EAI_NODATA */
"hostname nor servname provided, or not known", /* EAI_NONAME */
"servname not supported for ai_socktype", /* EAI_SERVICE */
"ai_socktype not supported", /* EAI_SOCKTYPE */
"System error returned in errno", /* EAI_SYSTEM */
"Invalid value for hints", /* EAI_BADHINTS */
"Resolved protocol is unknown", /* EAI_PROTOCOL */
"Unknown error", /* EAI_MAX */
};
/* XXX macros that make external reference is BAD. */
#define GET_AI(ai, afd, addr) \
do { \
/* external reference: pai, error, and label free */ \
(ai) = get_ai(pai, (afd), (addr)); \
if ((ai) == NULL) { \
error = EAI_MEMORY; \
goto free; \
} \
} while (/*CONSTCOND*/0)
#define GET_PORT(ai, serv) \
do { \
/* external reference: error and label free */ \
error = get_port((ai), (serv), 0); \
if (error != 0) \
goto free; \
} while (/*CONSTCOND*/0)
#define GET_CANONNAME(ai, str) \
do { \
/* external reference: pai, error and label free */ \
error = get_canonname(pai, (ai), (str)); \
if (error != 0) \
goto free; \
} while (/*CONSTCOND*/0)
#define ERR(err) \
do { \
/* external reference: error, and label bad */ \
error = (err); \
goto bad; \
/*NOTREACHED*/ \
} while (/*CONSTCOND*/0)
#define MATCH_FAMILY(x, y, w) \
((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC)))
#define MATCH(x, y, w) \
((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
char *
gai_strerror(ecode)
int ecode;
{
if (ecode < 0 || ecode > EAI_MAX)
ecode = EAI_MAX;
return ai_errlist[ecode];
}
void
freeaddrinfo(ai)
struct addrinfo *ai;
{
struct addrinfo *next;
do {
next = ai->ai_next;
if (ai->ai_canonname)
free(ai->ai_canonname);
/* no need to free(ai->ai_addr) */
free(ai);
ai = next;
} while (ai);
}
static int
str_isnumber(p)
const char *p;
{
char *ep;
if (*p == '\0')
return NO;
ep = NULL;
(void)strtoul(p, &ep, 10);
if (ep && *ep == '\0')
return YES;
else
return NO;
}
int
getaddrinfo(hostname, servname, hints, res)
const char *hostname, *servname;
const struct addrinfo *hints;
struct addrinfo **res;
{
struct addrinfo sentinel;
struct addrinfo *cur;
int error = 0;
struct addrinfo ai;
struct addrinfo ai0;
struct addrinfo *pai;
const struct explore *ex;
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
pai = &ai;
pai->ai_flags = 0;
pai->ai_family = PF_UNSPEC;
pai->ai_socktype = ANY;
pai->ai_protocol = ANY;
pai->ai_addrlen = 0;
pai->ai_canonname = NULL;
pai->ai_addr = NULL;
pai->ai_next = NULL;
if (hostname == NULL && servname == NULL)
return EAI_NONAME;
if (hints) {
/* error check for hints */
if (hints->ai_addrlen || hints->ai_canonname ||
hints->ai_addr || hints->ai_next)
ERR(EAI_BADHINTS); /* xxx */
if (hints->ai_flags & ~AI_MASK)
ERR(EAI_BADFLAGS);
switch (hints->ai_family) {
case PF_UNSPEC:
case PF_INET:
#ifdef INET6
case PF_INET6:
#endif
break;
default:
ERR(EAI_FAMILY);
}
memcpy(pai, hints, sizeof(*pai));
/*
* if both socktype/protocol are specified, check if they
* are meaningful combination.
*/
if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
for (ex = explore; ex->e_af >= 0; ex++) {
if (pai->ai_family != ex->e_af)
continue;
if (ex->e_socktype == ANY)
continue;
if (ex->e_protocol == ANY)
continue;
if (pai->ai_socktype == ex->e_socktype
&& pai->ai_protocol != ex->e_protocol) {
ERR(EAI_BADHINTS);
}
}
}
}
/*
* post-2553: AI_ALL and AI_V4MAPPED are effective only against
* AF_INET6 query. They needs to be ignored if specified in other
* occassions.
*/
switch (pai->ai_flags & (AI_ALL | AI_V4MAPPED)) {
case AI_V4MAPPED:
case AI_ALL | AI_V4MAPPED:
if (pai->ai_family != AF_INET6)
pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
break;
case AI_ALL:
#if 1
/* illegal */
ERR(EAI_BADFLAGS);
#else
pai->ai_flags &= ~(AI_ALL | AI_V4MAPPED);
#endif
break;
}
/*
* check for special cases. (1) numeric servname is disallowed if
* socktype/protocol are left unspecified. (2) servname is disallowed
* for raw and other inet{,6} sockets.
*/
if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
#ifdef PF_INET6
|| MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
#endif
) {
ai0 = *pai; /* backup *pai */
if (pai->ai_family == PF_UNSPEC) {
#ifdef PF_INET6
pai->ai_family = PF_INET6;
#else
pai->ai_family = PF_INET;
#endif
}
error = get_portmatch(pai, servname);
if (error)
ERR(error);
*pai = ai0;
}
ai0 = *pai;
/* NULL hostname, or numeric hostname */
for (ex = explore; ex->e_af >= 0; ex++) {
*pai = ai0;
/* PF_UNSPEC entries are prepared for DNS queries only */
if (ex->e_af == PF_UNSPEC)
continue;
if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
continue;
if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
continue;
if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
continue;
if (pai->ai_family == PF_UNSPEC)
pai->ai_family = ex->e_af;
if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
pai->ai_socktype = ex->e_socktype;
if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
pai->ai_protocol = ex->e_protocol;
if (hostname == NULL)
error = explore_null(pai, servname, &cur->ai_next);
else
error = explore_numeric_scope(pai, hostname, servname, &cur->ai_next);
if (error)
goto free;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
/*
* XXX
* If numreic representation of AF1 can be interpreted as FQDN
* representation of AF2, we need to think again about the code below.
*/
if (sentinel.ai_next)
goto good;
if (pai->ai_flags & AI_NUMERICHOST)
ERR(EAI_NONAME);
if (hostname == NULL)
ERR(EAI_NODATA);
if ((pai->ai_flags & AI_ADDRCONFIG) != 0 && !addrconfig(&ai0))
ERR(EAI_FAIL);
/*
* hostname as alphabetical name.
* we would like to prefer AF_INET6 than AF_INET, so we'll make a
* outer loop by AFs.
*/
for (ex = explore; ex->e_af >= 0; ex++) {
*pai = ai0;
/* require exact match for family field */
if (pai->ai_family != ex->e_af)
continue;
if (!MATCH(pai->ai_socktype, ex->e_socktype,
WILD_SOCKTYPE(ex))) {
continue;
}
if (!MATCH(pai->ai_protocol, ex->e_protocol,
WILD_PROTOCOL(ex))) {
continue;
}
if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
pai->ai_socktype = ex->e_socktype;
if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
pai->ai_protocol = ex->e_protocol;
error = explore_fqdn(pai, hostname, servname,
&cur->ai_next);
while (cur && cur->ai_next)
cur = cur->ai_next;
}
/* XXX */
if (sentinel.ai_next)
error = 0;
if (error)
goto free;
if (error == 0) {
if (sentinel.ai_next) {
good:
*res = sentinel.ai_next;
return SUCCESS;
} else
error = EAI_FAIL;
}
free:
bad:
if (sentinel.ai_next)
freeaddrinfo(sentinel.ai_next);
*res = NULL;
return error;
}
/*
* FQDN hostname, DNS lookup
*/
static int
explore_fqdn(pai, hostname, servname, res)
const struct addrinfo *pai;
const char *hostname;
const char *servname;
struct addrinfo **res;
{
struct addrinfo *result;
struct addrinfo *cur;
int error = 0;
static const ns_dtab dtab[] = {
NS_FILES_CB(_files_getaddrinfo, NULL)
{ NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
NS_NIS_CB(_yp_getaddrinfo, NULL)
{ 0 }
};
result = NULL;
/*
* if the servname does not match socktype/protocol, ignore it.
*/
if (get_portmatch(pai, servname) != 0)
return 0;
switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
default_dns_files, hostname, pai)) {
case NS_TRYAGAIN:
error = EAI_AGAIN;
goto free;
case NS_UNAVAIL:
error = EAI_FAIL;
goto free;
case NS_NOTFOUND:
error = EAI_NODATA;
goto free;
case NS_SUCCESS:
error = 0;
for (cur = result; cur; cur = cur->ai_next) {
GET_PORT(cur, servname);
/* canonname should be filled already */
}
break;
}
*res = result;
return 0;
free:
if (result)
freeaddrinfo(result);
return error;
}
/*
* hostname == NULL.
* passive socket -> anyaddr (0.0.0.0 or ::)
* non-passive socket -> localhost (127.0.0.1 or ::1)
*/
static int
explore_null(pai, servname, res)
const struct addrinfo *pai;
const char *servname;
struct addrinfo **res;
{
int s;
const struct afd *afd;
struct addrinfo *cur;
struct addrinfo sentinel;
int error;
*res = NULL;
sentinel.ai_next = NULL;
cur = &sentinel;
/*
* filter out AFs that are not supported by the kernel
* XXX errno?
*/
s = _socket(pai->ai_family, SOCK_DGRAM, 0);
if (s < 0) {
if (errno != EMFILE)
return 0;
} else
_close(s);
/*
* if the servname does not match socktype/protocol, ignore it.
*/
if (get_portmatch(pai, servname) != 0)
return 0;
afd = find_afd(pai->ai_family);
if (afd == NULL)
return 0;
if (pai->ai_flags & AI_PASSIVE) {
GET_AI(cur->ai_next, afd, afd->a_addrany);
/* xxx meaningless?
* GET_CANONNAME(cur->ai_next, "anyaddr");
*/
GET_PORT(cur->ai_next, servname);
} else {
GET_AI(cur->ai_next, afd, afd->a_loopback);
/* xxx meaningless?
* GET_CANONNAME(cur->ai_next, "localhost");
*/
GET_PORT(cur->ai_next, servname);
}
cur = cur->ai_next;
*res = sentinel.ai_next;
return 0;
free:
if (sentinel.ai_next)
freeaddrinfo(sentinel.ai_next);
return error;
}
/*
* numeric hostname
*/
static int
explore_numeric(pai, hostname, servname, res)
const struct addrinfo *pai;
const char *hostname;
const char *servname;
struct addrinfo **res;
{
const struct afd *afd;
struct addrinfo *cur;
struct addrinfo sentinel;
int error;
char pton[PTON_MAX];
*res = NULL;
sentinel.ai_next = NULL;
cur = &sentinel;
/*
* if the servname does not match socktype/protocol, ignore it.
*/
if (get_portmatch(pai, servname) != 0)
return 0;
afd = find_afd(pai->ai_family);
if (afd == NULL)
return 0;
switch (afd->a_af) {
#if 1 /*X/Open spec*/
case AF_INET:
if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
if (pai->ai_family == afd->a_af ||
pai->ai_family == PF_UNSPEC /*?*/) {
GET_AI(cur->ai_next, afd, pton);
GET_PORT(cur->ai_next, servname);
while (cur && cur->ai_next)
cur = cur->ai_next;
} else
ERR(EAI_FAMILY); /*xxx*/
}
break;
#endif
default:
if (inet_pton(afd->a_af, hostname, pton) == 1) {
if (pai->ai_family == afd->a_af ||
pai->ai_family == PF_UNSPEC /*?*/) {
GET_AI(cur->ai_next, afd, pton);
GET_PORT(cur->ai_next, servname);
while (cur && cur->ai_next)
cur = cur->ai_next;
} else
ERR(EAI_FAMILY); /*xxx*/
}
break;
}
*res = sentinel.ai_next;
return 0;
free:
bad:
if (sentinel.ai_next)
freeaddrinfo(sentinel.ai_next);
return error;
}
/*
* numeric hostname with scope
*/
static int
explore_numeric_scope(pai, hostname, servname, res)
const struct addrinfo *pai;
const char *hostname;
const char *servname;
struct addrinfo **res;
{
#if !defined(SCOPE_DELIMITER) || !defined(INET6)
return explore_numeric(pai, hostname, servname, res);
#else
const struct afd *afd;
struct addrinfo *cur;
int error;
char *cp, *hostname2 = NULL, *scope, *addr;
struct sockaddr_in6 *sin6;
/*
* if the servname does not match socktype/protocol, ignore it.
*/
if (get_portmatch(pai, servname) != 0)
return 0;
afd = find_afd(pai->ai_family);
if (afd == NULL)
return 0;
if (!afd->a_scoped)
return explore_numeric(pai, hostname, servname, res);
cp = strchr(hostname, SCOPE_DELIMITER);
if (cp == NULL)
return explore_numeric(pai, hostname, servname, res);
/*
* Handle special case of <scoped_address><delimiter><scope id>
*/
hostname2 = strdup(hostname);
if (hostname2 == NULL)
return EAI_MEMORY;
/* terminate at the delimiter */
hostname2[cp - hostname] = '\0';
addr = hostname2;
scope = cp + 1;
error = explore_numeric(pai, addr, servname, res);
if (error == 0) {
int scopeid;
for (cur = *res; cur; cur = cur->ai_next) {
if (cur->ai_family != AF_INET6)
continue;
sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
if ((scopeid = ip6_str2scopeid(scope, sin6)) == -1) {
free(hostname2);
return(EAI_NODATA); /* XXX: is return OK? */
}
sin6->sin6_scope_id = scopeid;
}
}
free(hostname2);
return error;
#endif
}
static int
get_canonname(pai, ai, str)
const struct addrinfo *pai;
struct addrinfo *ai;
const char *str;
{
if ((pai->ai_flags & AI_CANONNAME) != 0) {
ai->ai_canonname = (char *)malloc(strlen(str) + 1);
if (ai->ai_canonname == NULL)
return EAI_MEMORY;
strcpy(ai->ai_canonname, str);
}
return 0;
}
static struct addrinfo *
get_ai(pai, afd, addr)
const struct addrinfo *pai;
const struct afd *afd;
const char *addr;
{
char *p;
struct addrinfo *ai;
#ifdef FAITH
struct in6_addr faith_prefix;
char *fp_str;
int translate = 0;
#endif
#ifdef FAITH
/*
* Transfrom an IPv4 addr into a special IPv6 addr format for
* IPv6->IPv4 translation gateway. (only TCP is supported now)
*
* +-----------------------------------+------------+
* | faith prefix part (12 bytes) | embedded |
* | | IPv4 addr part (4 bytes)
* +-----------------------------------+------------+
*
* faith prefix part is specified as ascii IPv6 addr format
* in environmental variable GAI.
* For FAITH to work correctly, routing to faith prefix must be
* setup toward a machine where a FAITH daemon operates.
* Also, the machine must enable some mechanizm
* (e.g. faith interface hack) to divert those packet with
* faith prefixed destination addr to user-land FAITH daemon.
*/
fp_str = getenv("GAI");
if (fp_str && inet_pton(AF_INET6, fp_str, &faith_prefix) == 1 &&
afd->a_af == AF_INET && pai->ai_socktype == SOCK_STREAM) {
u_int32_t v4a;
u_int8_t v4a_top;
memcpy(&v4a, addr, sizeof v4a);
v4a_top = v4a >> IN_CLASSA_NSHIFT;
if (!IN_MULTICAST(v4a) && !IN_EXPERIMENTAL(v4a) &&
v4a_top != 0 && v4a != IN_LOOPBACKNET) {
afd = &afdl[N_INET6];
memcpy(&faith_prefix.s6_addr[12], addr,
sizeof(struct in_addr));
translate = 1;
}
}
#endif
ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
+ (afd->a_socklen));
if (ai == NULL)
return NULL;
memcpy(ai, pai, sizeof(struct addrinfo));
ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
ai->ai_addr->sa_len = afd->a_socklen;
ai->ai_addrlen = afd->a_socklen;
ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
p = (char *)(void *)(ai->ai_addr);
#ifdef FAITH
if (translate == 1)
memcpy(p + afd->a_off, &faith_prefix, (size_t)afd->a_addrlen);
else
#endif
memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
return ai;
}
static int
get_portmatch(ai, servname)
const struct addrinfo *ai;
const char *servname;
{
/* get_port does not touch first argument. when matchonly == 1. */
/* LINTED const cast */
return get_port((struct addrinfo *)ai, servname, 1);
}
static int
get_port(ai, servname, matchonly)
struct addrinfo *ai;
const char *servname;
int matchonly;
{
const char *proto;
struct servent *sp;
int port;
int allownumeric;
if (servname == NULL)
return 0;
switch (ai->ai_family) {
case AF_INET:
#ifdef AF_INET6
case AF_INET6:
#endif
break;
default:
return 0;
}
switch (ai->ai_socktype) {
case SOCK_RAW:
return EAI_SERVICE;
case SOCK_DGRAM:
case SOCK_STREAM:
allownumeric = 1;
break;
case ANY:
allownumeric = 0;
break;
default:
return EAI_SOCKTYPE;
}
if (str_isnumber(servname)) {
if (!allownumeric)
return EAI_SERVICE;
port = htons(atoi(servname));
if (port < 0 || port > 65535)
return EAI_SERVICE;
} else {
switch (ai->ai_socktype) {
case SOCK_DGRAM:
proto = "udp";
break;
case SOCK_STREAM:
proto = "tcp";
break;
default:
proto = NULL;
break;
}
if ((sp = getservbyname(servname, proto)) == NULL)
return EAI_SERVICE;
port = sp->s_port;
}
if (!matchonly) {
switch (ai->ai_family) {
case AF_INET:
((struct sockaddr_in *)(void *)
ai->ai_addr)->sin_port = port;
break;
#ifdef INET6
case AF_INET6:
((struct sockaddr_in6 *)(void *)
ai->ai_addr)->sin6_port = port;
break;
#endif
}
}
return 0;
}
static const struct afd *
find_afd(af)
int af;
{
const struct afd *afd;
if (af == PF_UNSPEC)
return NULL;
for (afd = afdl; afd->a_af; afd++) {
if (afd->a_af == af)
return afd;
}
return NULL;
}
/*
* post-2553: AI_ADDRCONFIG check. if we use getipnodeby* as backend, backend
* will take care of it.
* the semantics of AI_ADDRCONFIG is not defined well. we are not sure
* if the code is right or not.
*
* XXX PF_UNSPEC -> PF_INET6 + PF_INET mapping needs to be in sync with
* _dns_getaddrinfo.
*/
static int
addrconfig(pai)
struct addrinfo *pai;
{
int s, af;
/*
* TODO:
* Note that implementation dependent test for address
* configuration should be done everytime called
* (or apropriate interval),
* because addresses will be dynamically assigned or deleted.
*/
af = pai->ai_family;
if (af == AF_UNSPEC) {
if ((s = _socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
af = AF_INET;
else {
_close(s);
if ((s = _socket(AF_INET, SOCK_DGRAM, 0)) < 0)
af = AF_INET6;
else
_close(s);
}
}
if (af != AF_UNSPEC) {
if ((s = _socket(af, SOCK_DGRAM, 0)) < 0)
return 0;
_close(s);
}
pai->ai_family = af;
return 1;
}
#ifdef INET6
/* convert a string to a scope identifier. XXX: IPv6 specific */
static int
ip6_str2scopeid(scope, sin6)
char *scope;
struct sockaddr_in6 *sin6;
{
int scopeid;
struct in6_addr *a6 = &sin6->sin6_addr;
char *ep;
/* empty scopeid portion is invalid */
if (*scope == '\0')
return -1;
if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
/*
* We currently assume a one-to-one mapping between links
* and interfaces, so we simply use interface indices for
* like-local scopes.
*/
scopeid = if_nametoindex(scope);
if (scopeid == 0)
goto trynumeric;
return(scopeid);
}
/* still unclear about literal, allow numeric only - placeholder */
if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
goto trynumeric;
if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
goto trynumeric;
else
goto trynumeric; /* global */
/* try to convert to a numeric id as a last resort */
trynumeric:
scopeid = (int)strtoul(scope, &ep, 10);
if (*ep == '\0')
return scopeid;
else
return -1;
}
#endif
#ifdef DEBUG
static const char AskedForGot[] =
"gethostby*.getanswer: asked for \"%s\", got \"%s\"";
#endif
static FILE *hostf = NULL;
static struct addrinfo *
getanswer(answer, anslen, qname, qtype, pai)
const querybuf *answer;
int anslen;
const char *qname;
int qtype;
const struct addrinfo *pai;
{
struct addrinfo sentinel, *cur;
struct addrinfo ai;
const struct afd *afd;
char *canonname;
const HEADER *hp;
const u_char *cp;
int n;
const u_char *eom;
char *bp;
int type, class, buflen, ancount, qdcount;
int haveanswer, had_error;
char tbuf[MAXDNAME];
int (*name_ok) __P((const char *));
char hostbuf[8*1024];
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
canonname = NULL;
eom = answer->buf + anslen;
switch (qtype) {
case T_A:
case T_AAAA:
case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
name_ok = res_hnok;
break;
default:
return (NULL); /* XXX should be abort(); */
}
/*
* find first satisfactory answer
*/
hp = &answer->hdr;
ancount = ntohs(hp->ancount);
qdcount = ntohs(hp->qdcount);
bp = hostbuf;
buflen = sizeof hostbuf;
cp = answer->buf + HFIXEDSZ;
if (qdcount != 1) {
h_errno = NO_RECOVERY;
return (NULL);
}
n = dn_expand(answer->buf, eom, cp, bp, buflen);
if ((n < 0) || !(*name_ok)(bp)) {
h_errno = NO_RECOVERY;
return (NULL);
}
cp += n + QFIXEDSZ;
if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
/* res_send() has already verified that the query name is the
* same as the one we sent; this just gets the expanded name
* (i.e., with the succeeding search-domain tacked on).
*/
n = strlen(bp) + 1; /* for the \0 */
if (n >= MAXHOSTNAMELEN) {
h_errno = NO_RECOVERY;
return (NULL);
}
canonname = bp;
bp += n;
buflen -= n;
/* The qname can be abbreviated, but h_name is now absolute. */
qname = canonname;
}
haveanswer = 0;
had_error = 0;
while (ancount-- > 0 && cp < eom && !had_error) {
n = dn_expand(answer->buf, eom, cp, bp, buflen);
if ((n < 0) || !(*name_ok)(bp)) {
had_error++;
continue;
}
cp += n; /* name */
type = _getshort(cp);
cp += INT16SZ; /* type */
class = _getshort(cp);
cp += INT16SZ + INT32SZ; /* class, TTL */
n = _getshort(cp);
cp += INT16SZ; /* len */
if (class != C_IN) {
/* XXX - debug? syslog? */
cp += n;
continue; /* XXX - had_error++ ? */
}
if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
type == T_CNAME) {
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if ((n < 0) || !(*name_ok)(tbuf)) {
had_error++;
continue;
}
cp += n;
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > buflen || n >= MAXHOSTNAMELEN) {
had_error++;
continue;
}
strcpy(bp, tbuf);
canonname = bp;
bp += n;
buflen -= n;
continue;
}
if (qtype == T_ANY) {
if (!(type == T_A || type == T_AAAA)) {
cp += n;
continue;
}
} else if (type != qtype) {
#ifdef DEBUG
if (type != T_KEY && type != T_SIG)
syslog(LOG_NOTICE|LOG_AUTH,
"gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
qname, p_class(C_IN), p_type(qtype),
p_type(type));
#endif
cp += n;
continue; /* XXX - had_error++ ? */
}
switch (type) {
case T_A:
case T_AAAA:
if (strcasecmp(canonname, bp) != 0) {
#ifdef DEBUG
syslog(LOG_NOTICE|LOG_AUTH,
AskedForGot, canonname, bp);
#endif
cp += n;
continue; /* XXX - had_error++ ? */
}
if (type == T_A && n != INADDRSZ) {
cp += n;
continue;
}
if (type == T_AAAA && n != IN6ADDRSZ) {
cp += n;
continue;
}
#ifdef FILTER_V4MAPPED
if (type == T_AAAA) {
struct in6_addr in6;
memcpy(&in6, cp, sizeof(in6));
if (IN6_IS_ADDR_V4MAPPED(&in6)) {
cp += n;
continue;
}
}
#endif
if (!haveanswer) {
int nn;
canonname = bp;
nn = strlen(bp) + 1; /* for the \0 */
bp += nn;
buflen -= nn;
}
/* don't overwrite pai */
ai = *pai;
ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
afd = find_afd(ai.ai_family);
if (afd == NULL) {
cp += n;
continue;
}
cur->ai_next = get_ai(&ai, afd, (const char *)cp);
if (cur->ai_next == NULL)
had_error++;
while (cur && cur->ai_next)
cur = cur->ai_next;
cp += n;
break;
default:
abort();
}
if (!had_error)
haveanswer++;
}
if (haveanswer) {
if (!canonname)
(void)get_canonname(pai, sentinel.ai_next, qname);
else
(void)get_canonname(pai, sentinel.ai_next, canonname);
h_errno = NETDB_SUCCESS;
return sentinel.ai_next;
}
h_errno = NO_RECOVERY;
return NULL;
}
/*ARGSUSED*/
static int
_dns_getaddrinfo(rv, cb_data, ap)
void *rv;
void *cb_data;
va_list ap;
{
struct addrinfo *ai;
querybuf buf, buf2;
const char *name;
const struct addrinfo *pai;
struct addrinfo sentinel, *cur;
struct res_target q, q2;
name = va_arg(ap, char *);
pai = va_arg(ap, const struct addrinfo *);
memset(&q, 0, sizeof(q2));
memset(&q2, 0, sizeof(q2));
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
switch (pai->ai_family) {
case AF_UNSPEC:
/* prefer IPv6 */
q.qclass = C_IN;
q.qtype = T_AAAA;
q.answer = buf.buf;
q.anslen = sizeof(buf);
q.next = &q2;
q2.qclass = C_IN;
q2.qtype = T_A;
q2.answer = buf2.buf;
q2.anslen = sizeof(buf2);
break;
case AF_INET:
q.qclass = C_IN;
q.qtype = T_A;
q.answer = buf.buf;
q.anslen = sizeof(buf);
break;
case AF_INET6:
q.qclass = C_IN;
q.qtype = T_AAAA;
q.answer = buf.buf;
q.anslen = sizeof(buf);
break;
default:
return NS_UNAVAIL;
}
if (res_searchN(name, &q) < 0)
return NS_NOTFOUND;
ai = getanswer(&buf, q.n, q.name, q.qtype, pai);
if (ai) {
cur->ai_next = ai;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
if (q.next) {
ai = getanswer(&buf2, q2.n, q2.name, q2.qtype, pai);
if (ai)
cur->ai_next = ai;
}
if (sentinel.ai_next == NULL)
switch (h_errno) {
case HOST_NOT_FOUND:
return NS_NOTFOUND;
case TRY_AGAIN:
return NS_TRYAGAIN;
default:
return NS_UNAVAIL;
}
*((struct addrinfo **)rv) = sentinel.ai_next;
return NS_SUCCESS;
}
static void
_sethtent()
{
if (!hostf)
hostf = fopen(_PATH_HOSTS, "r" );
else
rewind(hostf);
}
static void
_endhtent()
{
if (hostf) {
(void) fclose(hostf);
hostf = NULL;
}
}
static struct addrinfo *
_gethtent(name, pai)
const char *name;
const struct addrinfo *pai;
{
char *p;
char *cp, *tname, *cname;
struct addrinfo hints, *res0, *res;
int error;
const char *addr;
char hostbuf[8*1024];
if (!hostf && !(hostf = fopen(_PATH_HOSTS, "r" )))
return (NULL);
again:
if (!(p = fgets(hostbuf, sizeof hostbuf, hostf)))
return (NULL);
if (*p == '#')
goto again;
if (!(cp = strpbrk(p, "#\n")))
goto again;
*cp = '\0';
if (!(cp = strpbrk(p, " \t")))
goto again;
*cp++ = '\0';
addr = p;
cname = NULL;
/* if this is not something we're looking for, skip it. */
while (cp && *cp) {
if (*cp == ' ' || *cp == '\t') {
cp++;
continue;
}
tname = cp;
if (cname == NULL)
cname = cp;
if ((cp = strpbrk(cp, " \t")) != NULL)
*cp++ = '\0';
if (strcasecmp(name, tname) == 0)
goto found;
}
goto again;
found:
hints = *pai;
hints.ai_flags = AI_NUMERICHOST;
error = getaddrinfo(addr, NULL, &hints, &res0);
if (error)
goto again;
#ifdef FILTER_V4MAPPED
/* XXX should check all items in the chain */
if (res0->ai_family == AF_INET6 &&
IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)res0->ai_addr)->sin6_addr)) {
freeaddrinfo(res0);
goto again;
}
#endif
for (res = res0; res; res = res->ai_next) {
/* cover it up */
res->ai_flags = pai->ai_flags;
if (pai->ai_flags & AI_CANONNAME) {
if (get_canonname(pai, res, cname) != 0) {
freeaddrinfo(res0);
goto again;
}
}
}
return res0;
}
/*ARGSUSED*/
static int
_files_getaddrinfo(rv, cb_data, ap)
void *rv;
void *cb_data;
va_list ap;
{
const char *name;
const struct addrinfo *pai;
struct addrinfo sentinel, *cur;
struct addrinfo *p;
name = va_arg(ap, char *);
pai = va_arg(ap, struct addrinfo *);
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
_sethtent();
while ((p = _gethtent(name, pai)) != NULL) {
cur->ai_next = p;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
_endhtent();
*((struct addrinfo **)rv) = sentinel.ai_next;
if (sentinel.ai_next == NULL)
return NS_NOTFOUND;
return NS_SUCCESS;
}
#ifdef YP
static char *__ypdomain;
/*ARGSUSED*/
static struct addrinfo *
_yphostent(line, pai)
char *line;
const struct addrinfo *pai;
{
struct addrinfo sentinel, *cur;
struct addrinfo hints, *res, *res0;
int error;
char *p = line;
const char *addr, *canonname;
char *nextline;
char *cp;
addr = canonname = NULL;
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
nextline:
/* terminate line */
cp = strchr(p, '\n');
if (cp) {
*cp++ = '\0';
nextline = cp;
} else
nextline = NULL;
cp = strpbrk(p, " \t");
if (cp == NULL) {
if (canonname == NULL)
return (NULL);
else
goto done;
}
*cp++ = '\0';
addr = p;
while (cp && *cp) {
if (*cp == ' ' || *cp == '\t') {
cp++;
continue;
}
if (!canonname)
canonname = cp;
if ((cp = strpbrk(cp, " \t")) != NULL)
*cp++ = '\0';
}
hints = *pai;
hints.ai_flags = AI_NUMERICHOST;
error = getaddrinfo(addr, NULL, &hints, &res0);
if (error == 0) {
for (res = res0; res; res = res->ai_next) {
/* cover it up */
res->ai_flags = pai->ai_flags;
if (pai->ai_flags & AI_CANONNAME)
(void)get_canonname(pai, res, canonname);
}
} else
res0 = NULL;
if (res0) {
cur->ai_next = res0;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
if (nextline) {
p = nextline;
goto nextline;
}
done:
return sentinel.ai_next;
}
/*ARGSUSED*/
static int
_yp_getaddrinfo(rv, cb_data, ap)
void *rv;
void *cb_data;
va_list ap;
{
struct addrinfo sentinel, *cur;
struct addrinfo *ai = NULL;
static char *__ypcurrent;
int __ypcurrentlen, r;
const char *name;
const struct addrinfo *pai;
name = va_arg(ap, char *);
pai = va_arg(ap, const struct addrinfo *);
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
if (!__ypdomain) {
if (_yp_check(&__ypdomain) == 0)
return NS_UNAVAIL;
}
if (__ypcurrent)
free(__ypcurrent);
__ypcurrent = NULL;
/* hosts.byname is only for IPv4 (Solaris8) */
if (pai->ai_family == PF_UNSPEC || pai->ai_family == PF_INET) {
r = yp_match(__ypdomain, "hosts.byname", name,
(int)strlen(name), &__ypcurrent, &__ypcurrentlen);
if (r == 0) {
struct addrinfo ai4;
ai4 = *pai;
ai4.ai_family = AF_INET;
ai = _yphostent(__ypcurrent, &ai4);
if (ai) {
cur->ai_next = ai;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
}
}
/* ipnodes.byname can hold both IPv4/v6 */
r = yp_match(__ypdomain, "ipnodes.byname", name,
(int)strlen(name), &__ypcurrent, &__ypcurrentlen);
if (r == 0) {
ai = _yphostent(__ypcurrent, pai);
if (ai) {
cur->ai_next = ai;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
}
if (sentinel.ai_next == NULL) {
h_errno = HOST_NOT_FOUND;
return NS_NOTFOUND;
}
*((struct addrinfo **)rv) = sentinel.ai_next;
return NS_SUCCESS;
}
#endif
/* resolver logic */
extern const char *__hostalias __P((const char *));
extern int h_errno;
/*
* Formulate a normal query, send, and await answer.
* Returned answer is placed in supplied buffer "answer".
* Perform preliminary check of answer, returning success only
* if no error is indicated and the answer count is nonzero.
* Return the size of the response on success, -1 on error.
* Error number is left in h_errno.
*
* Caller must parse answer and determine whether it answers the question.
*/
static int
res_queryN(name, target)
const char *name; /* domain name */
struct res_target *target;
{
u_char buf[MAXPACKET];
HEADER *hp;
int n;
struct res_target *t;
int rcode;
int ancount;
rcode = NOERROR;
ancount = 0;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return (-1);
}
for (t = target; t; t = t->next) {
int class, type;
u_char *answer;
int anslen;
hp = (HEADER *)(void *)t->answer;
hp->rcode = NOERROR; /* default */
/* make it easier... */
class = t->qclass;
type = t->qtype;
answer = t->answer;
anslen = t->anslen;
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf(";; res_query(%s, %d, %d)\n", name, class, type);
#endif
n = res_mkquery(QUERY, name, class, type, NULL, 0, NULL,
buf, sizeof(buf));
if (n > 0 && (_res.options & RES_USE_EDNS0) != 0)
n = res_opt(n, buf, sizeof(buf), anslen);
if (n <= 0) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf(";; res_query: mkquery failed\n");
#endif
h_errno = NO_RECOVERY;
return (n);
}
n = res_send(buf, n, answer, anslen);
#if 0
if (n < 0) {
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf(";; res_query: send error\n");
#endif
h_errno = TRY_AGAIN;
return (n);
}
#endif
if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
rcode = hp->rcode; /* record most recent error */
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf(";; rcode = %d, ancount=%d\n", hp->rcode,
ntohs(hp->ancount));
#endif
continue;
}
ancount += ntohs(hp->ancount);
t->n = n;
}
if (ancount == 0) {
switch (rcode) {
case NXDOMAIN:
h_errno = HOST_NOT_FOUND;
break;
case SERVFAIL:
h_errno = TRY_AGAIN;
break;
case NOERROR:
h_errno = NO_DATA;
break;
case FORMERR:
case NOTIMP:
case REFUSED:
default:
h_errno = NO_RECOVERY;
break;
}
return (-1);
}
return (ancount);
}
/*
* Formulate a normal query, send, and retrieve answer in supplied buffer.
* Return the size of the response on success, -1 on error.
* If enabled, implement search rules until answer or unrecoverable failure
* is detected. Error code, if any, is left in h_errno.
*/
static int
res_searchN(name, target)
const char *name; /* domain name */
struct res_target *target;
{
const char *cp, * const *domain;
HEADER *hp = (HEADER *)(void *)target->answer; /*XXX*/
u_int dots;
int trailing_dot, ret, saved_herrno;
int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return (-1);
}
errno = 0;
h_errno = HOST_NOT_FOUND; /* default, if we never query */
dots = 0;
for (cp = name; *cp; cp++)
dots += (*cp == '.');
trailing_dot = 0;
if (cp > name && *--cp == '.')
trailing_dot++;
/*
* if there aren't any dots, it could be a user-level alias
*/
if (!dots && (cp = __hostalias(name)) != NULL)
return (res_queryN(cp, target));
/*
* If there are dots in the name already, let's just give it a try
* 'as is'. The threshold can be set with the "ndots" option.
*/
saved_herrno = -1;
if (dots >= _res.ndots) {
ret = res_querydomainN(name, NULL, target);
if (ret > 0)
return (ret);
saved_herrno = h_errno;
tried_as_is++;
}
/*
* We do at least one level of search if
* - there is no dot and RES_DEFNAME is set, or
* - there is at least one dot, there is no trailing dot,
* and RES_DNSRCH is set.
*/
if ((!dots && (_res.options & RES_DEFNAMES)) ||
(dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
int done = 0;
for (domain = (const char * const *)_res.dnsrch;
*domain && !done;
domain++) {
ret = res_querydomainN(name, *domain, target);
if (ret > 0)
return (ret);
/*
* If no server present, give up.
* If name isn't found in this domain,
* keep trying higher domains in the search list
* (if that's enabled).
* On a NO_DATA error, keep trying, otherwise
* a wildcard entry of another type could keep us
* from finding this entry higher in the domain.
* If we get some other error (negative answer or
* server failure), then stop searching up,
* but try the input name below in case it's
* fully-qualified.
*/
if (errno == ECONNREFUSED) {
h_errno = TRY_AGAIN;
return (-1);
}
switch (h_errno) {
case NO_DATA:
got_nodata++;
/* FALLTHROUGH */
case HOST_NOT_FOUND:
/* keep trying */
break;
case TRY_AGAIN:
if (hp->rcode == SERVFAIL) {
/* try next search element, if any */
got_servfail++;
break;
}
/* FALLTHROUGH */
default:
/* anything else implies that we're done */
done++;
}
/*
* if we got here for some reason other than DNSRCH,
* we only wanted one iteration of the loop, so stop.
*/
if (!(_res.options & RES_DNSRCH))
done++;
}
}
/*
* if we have not already tried the name "as is", do that now.
* note that we do this regardless of how many dots were in the
* name or whether it ends with a dot.
*/
if (!tried_as_is && (dots || !(_res.options & RES_NOTLDQUERY))) {
ret = res_querydomainN(name, NULL, target);
if (ret > 0)
return (ret);
}
/*
* if we got here, we didn't satisfy the search.
* if we did an initial full query, return that query's h_errno
* (note that we wouldn't be here if that query had succeeded).
* else if we ever got a nodata, send that back as the reason.
* else send back meaningless h_errno, that being the one from
* the last DNSRCH we did.
*/
if (saved_herrno != -1)
h_errno = saved_herrno;
else if (got_nodata)
h_errno = NO_DATA;
else if (got_servfail)
h_errno = TRY_AGAIN;
return (-1);
}
/*
* Perform a call on res_query on the concatenation of name and domain,
* removing a trailing dot from name if domain is NULL.
*/
static int
res_querydomainN(name, domain, target)
const char *name, *domain;
struct res_target *target;
{
char nbuf[MAXDNAME];
const char *longname = nbuf;
size_t n, d;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
return (-1);
}
#ifdef DEBUG
if (_res.options & RES_DEBUG)
printf(";; res_querydomain(%s, %s)\n",
name, domain?domain:"<Nil>");
#endif
if (domain == NULL) {
/*
* Check for trailing '.';
* copy without '.' if present.
*/
n = strlen(name);
if (n >= MAXDNAME) {
h_errno = NO_RECOVERY;
return (-1);
}
if (n > 0 && name[--n] == '.') {
strncpy(nbuf, name, n);
nbuf[n] = '\0';
} else
longname = name;
} else {
n = strlen(name);
d = strlen(domain);
if (n + d + 1 >= MAXDNAME) {
h_errno = NO_RECOVERY;
return (-1);
}
sprintf(nbuf, "%s.%s", name, domain);
}
return (res_queryN(longname, target));
}
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